One common item that presents some interesting material property requirements is the container for carbonated beverages. The material used for this application must satisfy the following constraints 1
Provide a barrier to the passage of carbon dioxide which is under pressure in the container 2 be nontoxic unreactive with the beverage and preferably be recyclable 3 be relatively strong and capable of surviving a drop from a height of several feet when containing the beverage 4 be inexpensive and the cost to fabricate the final shape should be relative low 5 it optically transparent retain its optical clarity and 6 capable of being produced having different colors and/or able to be adorned with decorative lables.
All three of the basic material types metal (aluminum) ceramic(glass) and polymer(polyester plastic) are used for carbonated beverage containers(per the chapter-opening photographs for this chapter).
All of these materials are nontoxic and unreactive with beverage. In addition each material has its pros and cons. For example the aluminum alloy is relatively strong (but easily dented) is a very good barrier to the diffusion of carbon dioxide is easily recycled beverage are cooled rapidly and labels may be painted onto its surface. On the other hand the cans are optically opaque and relatively expensive to produce. Glass is impervious to the passage of carbon dioxide is a relatively in expensive material may be recycled but it cracks and fractures easily and glass bottles are relatively heavy. Whereas the plastic is relatively strong may be made optically transparent is inexpensive and lightweight and is recyclable it is not as impervious to the passage of carbon dioxide as the aluminum and glass. For example you may have noticed that beverage in aluminum and glass containers retain their carbonization (i.e. fizz) for several years whereas those in two-liter plastic bottles go flat within a few months.